Delhi-class

The Delhi class, designated Project 15, is a series of guided-missile destroyers operated by the Indian Navy. Development began in 1980 as a planned successor to the Godavari-class frigate. Following a 1983 Soviet offer of reversible gas turbines and updated weapon systems, the Directorate of Naval Design redesigned the vessels from frigates to destroyers. The design process incorporated inputs from the Severnoye Design Bureau and model testing conducted in Sweden and the Soviet Union. Construction by Mazagon Dock Limited was delayed by three years due to the dissolution of the Soviet Union and the subsequent disruption in the supply of weapon systems.

The hull design is a lengthened version of the Rajput class and integrates structural elements from the Godavari-class frigates and Soviet Sovremennyy-class destroyers. The class utilizes two Zorya-Mashproekt M36E gas turbine propulsion plants in a combined gas and gas configuration. The layout features staggered funnels and includes flag facilities to support command functions within a naval task group. The vessels are equipped for operations in nuclear, biological, and chemical warfare environments and provide hangar space for two Sea King Mk 42B helicopters.

The class has undergone mid-life refits to update its sensors and electronics. Initial air search radars have been replaced by Fregat M2EM and Lanza-N systems. Electronic warfare capabilities transitioned from the Ajanta system to the Ellora MK2, complemented by the Kavach anti-missile decoy system. Anti-submarine suites include hull-mounted sonars, while the class is being updated with towed array sonars. Combat management is handled by the BEL Shikari system, which integrates various indigenous and foreign components.

Armament has been modified throughout the service life of the class. The original AK-100 naval gun was replaced by the OTO Melara 76 mm gun and associated fire-control radars. Surface-to-air defense is provided by the Shtil-1 system, which is augmented by the Barak 1 point-defense missile system. The primary surface-to-surface missile battery, originally comprising Kh-35E Uran missiles, has been replaced with BrahMos cruise missiles utilizing modular slant launchers. For anti-submarine warfare, the ships utilize RBU-6000 rocket launchers and quintuple torpedo tubes.

The three vessels—INS Delhi, INS Mysore, and INS Mumbai—were commissioned between 1997 and 2001. The class is being re-based to the Eastern Naval Command at Visakhapatnam to operate as part of the carrier battle group for the aircraft carrier INS Vikrant.